Need help with this question. Convert temperatures to Kelvin

Question

1.)At 20 degrees celsius, a gas has a volume of 0.20 meter cube. The gas is heated until its volume doubles. What is its new temperature in Celsius degrees?

2.)A volume of 30 L of oxygen is cooled from 20 degrees celsius to -146.5 degrees celsius. What is its new volume?

3.) The volume f a sample of gas changes from 125 L to 75.0 L. If the new temperature is 225 degrees celsius, what was its original temperature in Celsius degrees?¯

Answer 1

1). To convert ºC to K (Kelvin), we add 273.15, so 20ºC = 293.15K.

V1 = initial volume = 0.20 m³ = 200 L

T1 = initial temperature = 293K

V2 = final volume = 400 L

T2 = final temperature = ?

V1/T1 = V2/T2

T2 = V2T1/V1 = 586K - 273 = 313ºC

2). V1 = 30 L

T1 = 20C + 273 = 293K

V2 = ?

T2 = -146.5C + 273 = 126.5

V1/T1 = V2/T2

V2 = V1T2 / T1

V2 = 13 L

3). V1 = 125 L

T1 = ?

V2 = 75 L

T2 = 225C + 273 = 498K

V1/T1 = V2/T2

T1 = V1T2 / V2

T1 = 830K -273 = 557ºC